The China Food and Drug Administration has warned citizens to beware of Staphylococcus aureus, a species of bacteria that secrete toxins.

Staphylococcus aureus can be found in the air and dirty water, and the bacteria prospers in carbuncles and festers in wounds. The microbes themselves prove harmless, but their reproduction gives rise to more than 20 types of enterotoxins, a category of toxins that affect human intestines. The toxins demonstrate a strong resistance to heat and remain toxic even when exposed to a temperature of 100 degrees Celsius for 30 minutes. Enterotoxins can also stand a high concentration of salt and can survive in solutions with a salt concentration of 10 percent.

Most experts believe that 20 to 25 micrograms of enterotoxin can sicken a human. Symptoms may include vomiting, diarrhea and stomachache. This acute and non-contagious sickness can end by itself in many cases and does not cause a fever. More serious cases would require medical care but rarely leave any after-effects.

The reproduction of Staphylococcus aureus can be accelerated by warm weather and the presence of proteins, carbohydrates and water. The bacteria multiply the fastest at a temperature of 37 degrees Celsius but cannot produce enterotoxins at a temperature below 5 degrees, so putting food in the fridge can effectively prevent food poisoning caused by the bacteria.

Foods containing starch, oil, milk, egg, fish, chicken or any cooked meat often provide Staphylococcus aureus with necessary nutrients. Companies producing these products should pay special attention to the quality of foods, voluntarily recalling anything that might contain the bacteria, according to the FDA.

Experts suggest that everyone should often wash hands to prevent Staphylococcus aureus from entering the food. Contaminated foods must not be eaten and should be separated.